Fixed missing run_time_cache for preloaded arena allocated internal functions

This effectively affected all preloaded enums, leading them to possibly share a run_time_cache__ptr slot with unrelated functions. (Given that these were not set again.)
This bugfix is not accompanied by a test, due to how hard to trigger it was and getting a crash also depends a lot on the precise alignment of whether a cache entry accidentally overlapping has been used etc.

NEWS

@@ -7,6 +7,7 @@ PHP                                                                        NEWS
     evaluation with extra named params). (Arnaud)
   . Fixed bug GH-9801 (Generator crashes when memory limit is exceeded during
     initialization). (Arnaud)
+  . Fixed a bug with preloaded enums possibly segfaulting. (Bob)
 
 - MySQLnd:
   . Fixed potential heap corruption due to alignment mismatch. (cmb)

ext/opcache/zend_persist.c

@@ -723,6 +723,7 @@ static void zend_persist_class_method(zval *zv, zend_class_entry *ce)
 						}
 					}
 				}
+				ZEND_MAP_PTR_NEW(op_array->run_time_cache);
 			}
 		}
 		return;